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1 /*
2  * Copyright 2006 The Android Open Source Project
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "SkStrike.h"
9 
10 #include "SkGraphics.h"
11 #include "SkMakeUnique.h"
12 #include "SkMutex.h"
13 #include "SkOnce.h"
14 #include "SkPath.h"
15 #include "SkTemplates.h"
16 #include "SkTypeface.h"
17 #include <cctype>
18 
19 namespace {
compute_path_size(const SkPath & path)20 size_t compute_path_size(const SkPath& path) {
21     return sizeof(SkPath) + path.countPoints() * sizeof(SkPoint);
22 }
23 }  // namespace
24 
SkStrike(const SkDescriptor & desc,std::unique_ptr<SkScalerContext> scaler,const SkFontMetrics & fontMetrics)25 SkStrike::SkStrike(
26     const SkDescriptor& desc,
27     std::unique_ptr<SkScalerContext> scaler,
28     const SkFontMetrics& fontMetrics)
29     : fDesc{desc}
30     , fScalerContext{std::move(scaler)}
31     , fFontMetrics{fontMetrics}
32     , fIsSubpixel{fScalerContext->isSubpixel()}
33     , fAxisAlignment{fScalerContext->computeAxisAlignmentForHText()}
34 {
35     SkASSERT(fScalerContext != nullptr);
36     fMemoryUsed = sizeof(*this);
37 }
38 
getDescriptor() const39 const SkDescriptor& SkStrike::getDescriptor() const {
40     return *fDesc.getDesc();
41 }
42 
43 #ifdef SK_DEBUG
44 #define VALIDATE()  AutoValidate av(this)
45 #else
46 #define VALIDATE()
47 #endif
48 
getGlyphCount() const49 unsigned SkStrike::getGlyphCount() const {
50     return fScalerContext->getGlyphCount();
51 }
52 
countCachedGlyphs() const53 int SkStrike::countCachedGlyphs() const {
54     return fGlyphMap.count();
55 }
56 
isGlyphCached(SkGlyphID glyphID,SkFixed x,SkFixed y) const57 bool SkStrike::isGlyphCached(SkGlyphID glyphID, SkFixed x, SkFixed y) const {
58     SkPackedGlyphID packedGlyphID{glyphID, x, y};
59     return fGlyphMap.find(packedGlyphID) != nullptr;
60 }
61 
getRawGlyphByID(SkPackedGlyphID id)62 SkGlyph* SkStrike::getRawGlyphByID(SkPackedGlyphID id) {
63     return lookupByPackedGlyphID(id, kNothing_MetricsType);
64 }
65 
getGlyphIDAdvance(uint16_t glyphID)66 const SkGlyph& SkStrike::getGlyphIDAdvance(uint16_t glyphID) {
67     VALIDATE();
68     SkPackedGlyphID packedGlyphID(glyphID);
69     return *this->lookupByPackedGlyphID(packedGlyphID, kJustAdvance_MetricsType);
70 }
71 
getGlyphIDMetrics(uint16_t glyphID)72 const SkGlyph& SkStrike::getGlyphIDMetrics(uint16_t glyphID) {
73     VALIDATE();
74     SkPackedGlyphID packedGlyphID(glyphID);
75     return *this->lookupByPackedGlyphID(packedGlyphID, kFull_MetricsType);
76 }
77 
getGlyphIDMetrics(uint16_t glyphID,SkFixed x,SkFixed y)78 const SkGlyph& SkStrike::getGlyphIDMetrics(uint16_t glyphID, SkFixed x, SkFixed y) {
79     VALIDATE();
80     SkPackedGlyphID packedGlyphID(glyphID, x, y);
81     return *this->lookupByPackedGlyphID(packedGlyphID, kFull_MetricsType);
82 }
83 
getAdvances(SkSpan<const SkGlyphID> glyphIDs,SkPoint advances[])84 void SkStrike::getAdvances(SkSpan<const SkGlyphID> glyphIDs, SkPoint advances[]) {
85     for (auto glyphID : glyphIDs) {
86         auto glyph = this->getGlyphIDAdvance(glyphID);
87         *advances++ = SkPoint::Make(glyph.fAdvanceX, glyph.fAdvanceY);
88     }
89 }
90 
lookupByPackedGlyphID(SkPackedGlyphID packedGlyphID,MetricsType type)91 SkGlyph* SkStrike::lookupByPackedGlyphID(SkPackedGlyphID packedGlyphID, MetricsType type) {
92     SkGlyph* glyphPtr = fGlyphMap.findOrNull(packedGlyphID);
93 
94     if (nullptr == glyphPtr) {
95         glyphPtr = this->allocateNewGlyph(packedGlyphID, type);
96         fGlyphMap.set(glyphPtr);
97     } else {
98         if (type == kFull_MetricsType && glyphPtr->isJustAdvance()) {
99             fScalerContext->getMetrics(glyphPtr);
100         }
101     }
102     return glyphPtr;
103 }
104 
allocateNewGlyph(SkPackedGlyphID packedGlyphID,MetricsType mtype)105 SkGlyph* SkStrike::allocateNewGlyph(SkPackedGlyphID packedGlyphID, MetricsType mtype) {
106     fMemoryUsed += sizeof(SkGlyph);
107 
108     SkGlyph* glyphPtr = fAlloc.make<SkGlyph>(packedGlyphID);
109     fGlyphMap.set(glyphPtr);
110 
111     if (kNothing_MetricsType == mtype) {
112         return glyphPtr;
113     } else if (kJustAdvance_MetricsType == mtype) {
114         fScalerContext->getAdvance(glyphPtr);
115     } else {
116         SkASSERT(kFull_MetricsType == mtype);
117         fScalerContext->getMetrics(glyphPtr);
118     }
119 
120     SkASSERT(glyphPtr->fID != SkPackedGlyphID());
121     return glyphPtr;
122 }
123 
findImage(const SkGlyph & glyph)124 const void* SkStrike::findImage(const SkGlyph& glyph) {
125     if (glyph.fWidth > 0 && glyph.fWidth < kMaxGlyphWidth) {
126         if (nullptr == glyph.fImage) {
127             SkDEBUGCODE(SkMask::Format oldFormat = (SkMask::Format)glyph.fMaskFormat);
128             size_t  size = const_cast<SkGlyph&>(glyph).allocImage(&fAlloc);
129             // check that alloc() actually succeeded
130             if (glyph.fImage) {
131                 fScalerContext->getImage(glyph);
132                 // TODO: the scaler may have changed the maskformat during
133                 // getImage (e.g. from AA or LCD to BW) which means we may have
134                 // overallocated the buffer. Check if the new computedImageSize
135                 // is smaller, and if so, strink the alloc size in fImageAlloc.
136                 fMemoryUsed += size;
137             }
138             SkASSERT(oldFormat == glyph.fMaskFormat);
139         }
140     }
141     return glyph.fImage;
142 }
143 
initializeImage(const volatile void * data,size_t size,SkGlyph * glyph)144 void SkStrike::initializeImage(const volatile void* data, size_t size, SkGlyph* glyph) {
145     // Don't overwrite the image if we already have one. We could have used a fallback if the
146     // glyph was missing earlier.
147     if (glyph->fImage) return;
148 
149     if (glyph->fWidth > 0 && glyph->fWidth < kMaxGlyphWidth) {
150         size_t allocSize = glyph->allocImage(&fAlloc);
151         // check that alloc() actually succeeded
152         if (glyph->fImage) {
153             SkASSERT(size == allocSize);
154             memcpy(glyph->fImage, const_cast<const void*>(data), allocSize);
155             fMemoryUsed += size;
156         }
157     }
158 }
159 
findPath(const SkGlyph & glyph)160 const SkPath* SkStrike::findPath(const SkGlyph& glyph) {
161 
162     if (!glyph.isEmpty()) {
163         // If the path already exists, return it.
164         if (glyph.fPathData != nullptr) {
165             if (glyph.fPathData->fHasPath) {
166                 return &glyph.fPathData->fPath;
167             }
168             return nullptr;
169         }
170 
171         const_cast<SkGlyph&>(glyph).addPath(fScalerContext.get(), &fAlloc);
172         if (glyph.fPathData != nullptr) {
173             fMemoryUsed += compute_path_size(glyph.fPathData->fPath);
174         }
175 
176         return glyph.path();
177     }
178 
179     return nullptr;
180 }
181 
initializePath(SkGlyph * glyph,const volatile void * data,size_t size)182 bool SkStrike::initializePath(SkGlyph* glyph, const volatile void* data, size_t size) {
183     // Don't overwrite the path if we already have one. We could have used a fallback if the
184     // glyph was missing earlier.
185     if (glyph->fPathData) return true;
186 
187     if (glyph->fWidth) {
188         SkGlyph::PathData* pathData = fAlloc.make<SkGlyph::PathData>();
189         glyph->fPathData = pathData;
190         auto path = skstd::make_unique<SkPath>();
191         if (!pathData->fPath.readFromMemory(const_cast<const void*>(data), size)) {
192             return false;
193         }
194         fMemoryUsed += compute_path_size(glyph->fPathData->fPath);
195         pathData->fHasPath = true;
196     }
197 
198     return true;
199 }
200 
belongsToCache(const SkGlyph * glyph) const201 bool SkStrike::belongsToCache(const SkGlyph* glyph) const {
202     return glyph && fGlyphMap.findOrNull(glyph->getPackedID()) == glyph;
203 }
204 
getCachedGlyphAnySubPix(SkGlyphID glyphID,SkPackedGlyphID vetoID) const205 const SkGlyph* SkStrike::getCachedGlyphAnySubPix(SkGlyphID glyphID,
206                                                      SkPackedGlyphID vetoID) const {
207     for (SkFixed subY = 0; subY < SK_Fixed1; subY += SK_FixedQuarter) {
208         for (SkFixed subX = 0; subX < SK_Fixed1; subX += SK_FixedQuarter) {
209             SkPackedGlyphID packedGlyphID{glyphID, subX, subY};
210             if (packedGlyphID == vetoID) continue;
211             if (SkGlyph* glyphPtr = fGlyphMap.findOrNull(packedGlyphID)) {
212                 return glyphPtr;
213             }
214         }
215     }
216 
217     return nullptr;
218 }
219 
initializeGlyphFromFallback(SkGlyph * glyph,const SkGlyph & fallback)220 void SkStrike::initializeGlyphFromFallback(SkGlyph* glyph, const SkGlyph& fallback) {
221     fMemoryUsed += glyph->copyImageData(fallback, &fAlloc);
222 }
223 
rounding() const224 SkVector SkStrike::rounding() const {
225     return SkStrikeCommon::PixelRounding(fIsSubpixel, fAxisAlignment);
226 }
227 
getGlyphMetrics(SkGlyphID glyphID,SkPoint position)228 const SkGlyph& SkStrike::getGlyphMetrics(SkGlyphID glyphID, SkPoint position) {
229     if (!fIsSubpixel) {
230         return this->getGlyphIDMetrics(glyphID);
231     } else {
232         SkIPoint lookupPosition = SkStrikeCommon::SubpixelLookup(fAxisAlignment, position);
233 
234         return this->getGlyphIDMetrics(glyphID, lookupPosition.x(), lookupPosition.y());
235     }
236 }
237 
238 #include "../pathops/SkPathOpsCubic.h"
239 #include "../pathops/SkPathOpsQuad.h"
240 
quad_in_bounds(const SkScalar * pts,const SkScalar bounds[2])241 static bool quad_in_bounds(const SkScalar* pts, const SkScalar bounds[2]) {
242     SkScalar min = SkTMin(SkTMin(pts[0], pts[2]), pts[4]);
243     if (bounds[1] < min) {
244         return false;
245     }
246     SkScalar max = SkTMax(SkTMax(pts[0], pts[2]), pts[4]);
247     return bounds[0] < max;
248 }
249 
cubic_in_bounds(const SkScalar * pts,const SkScalar bounds[2])250 static bool cubic_in_bounds(const SkScalar* pts, const SkScalar bounds[2]) {
251     SkScalar min = SkTMin(SkTMin(SkTMin(pts[0], pts[2]), pts[4]), pts[6]);
252     if (bounds[1] < min) {
253         return false;
254     }
255     SkScalar max = SkTMax(SkTMax(SkTMax(pts[0], pts[2]), pts[4]), pts[6]);
256     return bounds[0] < max;
257 }
258 
OffsetResults(const SkGlyph::Intercept * intercept,SkScalar scale,SkScalar xPos,SkScalar * array,int * count)259 void SkStrike::OffsetResults(const SkGlyph::Intercept* intercept, SkScalar scale,
260                                  SkScalar xPos, SkScalar* array, int* count) {
261     if (array) {
262         array += *count;
263         for (int index = 0; index < 2; index++) {
264             *array++ = intercept->fInterval[index] * scale + xPos;
265         }
266     }
267     *count += 2;
268 }
269 
AddInterval(SkScalar val,SkGlyph::Intercept * intercept)270 void SkStrike::AddInterval(SkScalar val, SkGlyph::Intercept* intercept) {
271     intercept->fInterval[0] = SkTMin(intercept->fInterval[0], val);
272     intercept->fInterval[1] = SkTMax(intercept->fInterval[1], val);
273 }
274 
AddPoints(const SkPoint * pts,int ptCount,const SkScalar bounds[2],bool yAxis,SkGlyph::Intercept * intercept)275 void SkStrike::AddPoints(const SkPoint* pts, int ptCount, const SkScalar bounds[2],
276         bool yAxis, SkGlyph::Intercept* intercept) {
277     for (int i = 0; i < ptCount; ++i) {
278         SkScalar val = *(&pts[i].fY - yAxis);
279         if (bounds[0] < val && val < bounds[1]) {
280             AddInterval(*(&pts[i].fX + yAxis), intercept);
281         }
282     }
283 }
284 
AddLine(const SkPoint pts[2],SkScalar axis,bool yAxis,SkGlyph::Intercept * intercept)285 void SkStrike::AddLine(const SkPoint pts[2], SkScalar axis, bool yAxis,
286                            SkGlyph::Intercept* intercept) {
287     SkScalar t = yAxis ? sk_ieee_float_divide(axis - pts[0].fX, pts[1].fX - pts[0].fX)
288                        : sk_ieee_float_divide(axis - pts[0].fY, pts[1].fY - pts[0].fY);
289     if (0 <= t && t < 1) {   // this handles divide by zero above
290         AddInterval(yAxis ? pts[0].fY + t * (pts[1].fY - pts[0].fY)
291             : pts[0].fX + t * (pts[1].fX - pts[0].fX), intercept);
292     }
293 }
294 
AddQuad(const SkPoint pts[3],SkScalar axis,bool yAxis,SkGlyph::Intercept * intercept)295 void SkStrike::AddQuad(const SkPoint pts[3], SkScalar axis, bool yAxis,
296                      SkGlyph::Intercept* intercept) {
297     SkDQuad quad;
298     quad.set(pts);
299     double roots[2];
300     int count = yAxis ? quad.verticalIntersect(axis, roots)
301             : quad.horizontalIntersect(axis, roots);
302     while (--count >= 0) {
303         SkPoint pt = quad.ptAtT(roots[count]).asSkPoint();
304         AddInterval(*(&pt.fX + yAxis), intercept);
305     }
306 }
307 
AddCubic(const SkPoint pts[4],SkScalar axis,bool yAxis,SkGlyph::Intercept * intercept)308 void SkStrike::AddCubic(const SkPoint pts[4], SkScalar axis, bool yAxis,
309                       SkGlyph::Intercept* intercept) {
310     SkDCubic cubic;
311     cubic.set(pts);
312     double roots[3];
313     int count = yAxis ? cubic.verticalIntersect(axis, roots)
314             : cubic.horizontalIntersect(axis, roots);
315     while (--count >= 0) {
316         SkPoint pt = cubic.ptAtT(roots[count]).asSkPoint();
317         AddInterval(*(&pt.fX + yAxis), intercept);
318     }
319 }
320 
MatchBounds(const SkGlyph * glyph,const SkScalar bounds[2])321 const SkGlyph::Intercept* SkStrike::MatchBounds(const SkGlyph* glyph,
322                                                     const SkScalar bounds[2]) {
323     if (!glyph->fPathData) {
324         return nullptr;
325     }
326     const SkGlyph::Intercept* intercept = glyph->fPathData->fIntercept;
327     while (intercept) {
328         if (bounds[0] == intercept->fBounds[0] && bounds[1] == intercept->fBounds[1]) {
329             return intercept;
330         }
331         intercept = intercept->fNext;
332     }
333     return nullptr;
334 }
335 
findIntercepts(const SkScalar bounds[2],SkScalar scale,SkScalar xPos,bool yAxis,SkGlyph * glyph,SkScalar * array,int * count)336 void SkStrike::findIntercepts(const SkScalar bounds[2], SkScalar scale, SkScalar xPos,
337         bool yAxis, SkGlyph* glyph, SkScalar* array, int* count) {
338     const SkGlyph::Intercept* match = MatchBounds(glyph, bounds);
339 
340     if (match) {
341         if (match->fInterval[0] < match->fInterval[1]) {
342             OffsetResults(match, scale, xPos, array, count);
343         }
344         return;
345     }
346 
347     SkGlyph::Intercept* intercept = fAlloc.make<SkGlyph::Intercept>();
348     intercept->fNext = glyph->fPathData->fIntercept;
349     intercept->fBounds[0] = bounds[0];
350     intercept->fBounds[1] = bounds[1];
351     intercept->fInterval[0] = SK_ScalarMax;
352     intercept->fInterval[1] = SK_ScalarMin;
353     glyph->fPathData->fIntercept = intercept;
354     const SkPath* path = &(glyph->fPathData->fPath);
355     const SkRect& pathBounds = path->getBounds();
356     if (*(&pathBounds.fBottom - yAxis) < bounds[0] || bounds[1] < *(&pathBounds.fTop - yAxis)) {
357         return;
358     }
359     SkPath::Iter iter(*path, false);
360     SkPoint pts[4];
361     SkPath::Verb verb;
362     while (SkPath::kDone_Verb != (verb = iter.next(pts))) {
363         switch (verb) {
364             case SkPath::kMove_Verb:
365                 break;
366             case SkPath::kLine_Verb:
367                 AddLine(pts, bounds[0], yAxis, intercept);
368                 AddLine(pts, bounds[1], yAxis, intercept);
369                 AddPoints(pts, 2, bounds, yAxis, intercept);
370                 break;
371             case SkPath::kQuad_Verb:
372                 if (!quad_in_bounds(&pts[0].fY - yAxis, bounds)) {
373                     break;
374                 }
375                 AddQuad(pts, bounds[0], yAxis, intercept);
376                 AddQuad(pts, bounds[1], yAxis, intercept);
377                 AddPoints(pts, 3, bounds, yAxis, intercept);
378                 break;
379             case SkPath::kConic_Verb:
380                 SkASSERT(0);  // no support for text composed of conics
381                 break;
382             case SkPath::kCubic_Verb:
383                 if (!cubic_in_bounds(&pts[0].fY - yAxis, bounds)) {
384                     break;
385                 }
386                 AddCubic(pts, bounds[0], yAxis, intercept);
387                 AddCubic(pts, bounds[1], yAxis, intercept);
388                 AddPoints(pts, 4, bounds, yAxis, intercept);
389                 break;
390             case SkPath::kClose_Verb:
391                 break;
392             default:
393                 SkASSERT(0);
394                 break;
395         }
396     }
397     if (intercept->fInterval[0] >= intercept->fInterval[1]) {
398         intercept->fInterval[0] = SK_ScalarMax;
399         intercept->fInterval[1] = SK_ScalarMin;
400         return;
401     }
402     OffsetResults(intercept, scale, xPos, array, count);
403 }
404 
dump() const405 void SkStrike::dump() const {
406     const SkTypeface* face = fScalerContext->getTypeface();
407     const SkScalerContextRec& rec = fScalerContext->getRec();
408     SkMatrix matrix;
409     rec.getSingleMatrix(&matrix);
410     matrix.preScale(SkScalarInvert(rec.fTextSize), SkScalarInvert(rec.fTextSize));
411     SkString name;
412     face->getFamilyName(&name);
413 
414     SkString msg;
415     SkFontStyle style = face->fontStyle();
416     msg.printf("cache typeface:%x %25s:(%d,%d,%d)\n %s glyphs:%3d",
417                face->uniqueID(), name.c_str(), style.weight(), style.width(), style.slant(),
418                rec.dump().c_str(), fGlyphMap.count());
419     SkDebugf("%s\n", msg.c_str());
420 }
421 
hasImage(const SkGlyph & glyph)422 bool SkStrike::hasImage(const SkGlyph& glyph) {
423     return !glyph.isEmpty() && this->findImage(glyph) != nullptr;
424 }
425 
hasPath(const SkGlyph & glyph)426 bool SkStrike::hasPath(const SkGlyph& glyph) {
427     return !glyph.isEmpty() && this->findPath(glyph) != nullptr;
428 }
429 
430 #ifdef SK_DEBUG
forceValidate() const431 void SkStrike::forceValidate() const {
432     size_t memoryUsed = sizeof(*this);
433     fGlyphMap.foreach ([&memoryUsed](const SkGlyph* glyphPtr) {
434         memoryUsed += sizeof(SkGlyph);
435         if (glyphPtr->fImage) {
436             memoryUsed += glyphPtr->computeImageSize();
437         }
438         if (glyphPtr->fPathData) {
439             memoryUsed += compute_path_size(glyphPtr->fPathData->fPath);
440         }
441     });
442     SkASSERT(fMemoryUsed == memoryUsed);
443 }
444 
validate() const445 void SkStrike::validate() const {
446 #ifdef SK_DEBUG_GLYPH_CACHE
447     forceValidate();
448 #endif
449 }
450 #endif
451 
452 
453